


Mabel Pines and her brother's soulmate

by Beelzebub_fuckers



Category: Gravity Falls
Genre: Awkward Tension, Family Shenanigans, M/M, Romantic Soulmates, Sequel, Soul Bond, Soulmate-Identifying Marks, Soulmates
Language: English
Status: Completed
Published: 2020-05-02
Updated: 2020-05-02
Packaged: 2021-03-02 04:08:00
Rating: Not Rated
Warnings: Underage
Chapters: 1
Words: 2,575
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23958946
Author URL: https://archiveofourown.org/users/Beelzebub_fuckers/pseuds/Beelzebub_fuckers
Summary: Bill Cipher realizes the painful truth. He is NEVER going to get Dipper to date him if he doesn't earn Mabel's approval. Now he has to try to undo the entire summer of antagonism plus the hatred she feels for him kidnapping her brother. Can the all-powerful Bill earn a 13-year-old girl's approval?
Relationships: Bill Cipher/Dipper Pines
Comments: 7
Kudos: 165
Collections: Bound to you through the Ursa Major





	Mabel Pines and her brother's soulmate

**Author's Note:**

> Hey guys! There was a LOT of unused ideas I had from writing the Ursa Major story. It's hard to have two people fall in love when they're literally stuck in one room for the entire story. As well as the fact that the rest of the Pines family didn't really do much except sit around and angst/cry over the fact that Dipper had been kidnapped. So I'm going to post, like, sequels! I made a collection so I can lump them all together and you guys can enjoy the Ursa Major content that I always dreamed of writing. This one is set sometime between the time Bill returns with Dipper and the last chapter of the original Ursa Major. So sit back and enjoy Bill trying to ask Mabel's permission to court her brother.

Stan had been pissed off ever since Bill had abruptly moved into their house. He wasn’t the only one. Pretty much every person living or working in the Mystery Shack was unwilling to trust or accept Bill. They begrudgingly allowed it out of fear that Bill would take Dipper away again, but that doesn’t mean they didn’t complain. They complained like they believed he would be forced out of the house if they did so loud enough. Bill, in turn, tolerated it. Because Dipper wanted him to get along with his dumb human family. So he earned his keep by doing whatever chores Stan wanted him to do in the Mystery Shack and pretending to not see Stan’s scathing glares.

For now, he was sweeping the shop and pushing merchandise onto shelves. Wendy sat at the register; magazine propped up in front of her face. She didn’t do much work in the Shack, but Stan kept her around anyway for reasons beyond Bill’s comprehension. Her friends often walked in during working hours and hung around the register, chatting with her about inane teenage bullshit. Today it was Robbie Valentino. Token edgy kid of Gravity Falls.

“Wendy. What’s up.” He said casually, leaning against the counter. His behavior was tolerable at best, Bill was amused by his “intimidating” glares and manly posturing. Wendy looked over his magazine at him.

“Hey, Robbie. Nothing much. Just running down the clock here. Nobody comes in fall, anyway.”

Robbie gave Bill a disgusted look. “Ugh. Why do they keep a literal world ending demon around this place? You’d think it’d drive customers away.”

“Outsiders don’t know he’s a demon.” Wendy said, they were talking pretty loudly. They clearly didn’t care whether or not he was listening. Bill thought they should be more nervous around a demon who reversed gravity and turned them into stone. “Besides, we’re keeping him around for Dipper’s sake. You know how it is.”

“Ugh. Right. He’s _dating_ that thing. Gross.” Robbie scoffed.

“Not his fault, dude. He’s doing it for us.” Wendy said, finally having the decency to whisper. “Don’t let Dipper hear you say that. You know how he feels about it.”

“Right. Whatever.” Robbie rolled his eyes. “Can’t you guys stop it? Don’t guys need to like, ask the permission of the men of the house? Shouldn’t Stan say no?”

Wendy laughed. “I don’t think you asked my dad when we dated. Did you ask Tambry’s dad? It’s 2013, dude. That’s really old fashioned. Besides, if anything he needs Mabel’s permission. Dipper does things with or without Stan’s permission. But Mabel? Come on dude. Mabel would get final say in Dipper’s love life.”

Bill’s ears twitched hearing this. Of course! How could he overlook something so important? Mabel was the most important person in Dipper’s life. Even more so than Bill, a fact that irritated him to no end. He sold his freedom for his sister, and would do so a hundred more times. If he wanted to keep Dipper forever, he would need the approval of his silly twin sister. Unfortunately, Mabel felt just as much disdain as any other person living in the Shack. She was a tough nut to crack. But Bill was the master of manipulation. How hard could it be to convince a teenage girl?

* * *

Bill had underestimated his opponent.

Mabel held a grudge longer than Stan’s list of arrest warrants. She was extremely mistrustful and angry at Bill. Anytime he attempted to talk to her, or even entered the same _room_ as her, she’d leave in a huff. The only time she deigned to be around him was when he was accompanied by her brother. She’d be super friendly to him then, laughing, hugging, cheerful Mabel antics, with the coldest eyes Bill had ever seen on a human. _If looks could kill._ She did not forgive him. If she had her way, she never would. After a week of efforts, Bill was beginning to lose hope. Especially because Dipper was beginning to pick up on Mabel’s hatred for Bill. It was causing doubt in his human. _That_ Bill could not stand. He had worked too hard for Dipper’s trust and he was not going to let some glitter-obsessed little girl stand between him and his soulmate.

“Mabe, babe!” Bill drawled, floating into the living room. Mabel laid across Stan’s armchair, knitting her newest sweater and watching Ducktective reruns. She gave Bill another one of her signature glares when he addressed her. “Now, listen, Shooting Star. I normally don’t interest myself with human feelings. Especially if they’re not Pine Tree’s. But I’ve noticed some, let’s say tension between us.”

“Tension.” Mabel repeated flatly.

“Yeah! Tension.” Bill said, like he was referring to an inside joke she was in on. Mabel did not smile. “What’s it going to take for you to give me a smile? Talk to me! I want us to have a great relationship from now on.”

“I don’t see why you would need any of that.” Mabel said, her tone clipped. “You certainly never needed my approval for anything before.”

“Well, why wouldn’t I want to be in good standing with my future sister in law?” Mabel rolled her eyes at him as he said that. “Shooting Star, it would make me _eternally_ grateful if you could approve of me.”

“Is _that_ what this is about?” Mabel scoffed. “Never. You kidnapped by brother! And threatened to kill me. And tricked me. Remember that time you broke into my Grunkle’s mind and tried to steal our property from us? Oh, or the time you tortured my Grunkle Ford!” Bill nodded. Yes, he did remember those things! And he even regretted some of them. Especially looking at Mabel’s disgusted face. “I am _never_ going to give you my Mabel seal of approval so you can drop it right there!”

Bill sighed. “Alright, kid.” He floated away in what he hoped was a suitably dramatic manner. He would just have to switch to more aggressive tactics.

He was _exceptionally_ sweet to Mabel Pines over the coming weeks. He got her the cutest sprinkles he could find, and attempted to soften her heart with offers to take over her chores. He only addressed her in the most respectful manner, and never teased or pranked her. He was the angel a demon despised.

So _why_ wasn’t it working?!

If anything, Mabel was only _more_ cold towards him! She stopped acting polite in front of Dipper. Treating him with irritated disdain and haughty behavior he had never thought possible from the sunny girl. She was the sweetest girl in the Falls. So how was it possible for her to be so bitchy? She made underhanded quips about him being a monster, and a demon, and a murderer. He _was_ all of those things. No doubt. And proud of them too. But he pretended not to be for Dipper. He put all of his violent hobbies on hold to appease his soulmate and worked hard to maintain their strict human morals. It was really starting to dampen Bill’s mood. What was the point of changing if no one believed in him?

He laid over Dipper’s side with a sigh, the human looking at the wilting demon with concern. “What’s wrong?” He asked.

“At least you care.” Bill sighed dramatically. Dipper laughed, and a smile tugged at the corners of Bill’s lips.

“Aw, has someone been mistreating my poor Bill?” Dipper asked sarcastically. Bill only pouted at the human’s callousness.

“Yes! Haven’t you noticed? Mabel has been mean and rude to me!” Bill complained.

“Mabel?” Dipper said, disbelieving. He wracked his memories of the past week, realizing his sister _had_ been acting strangely towards Bill and the subject of him. “Oh, yes. People don’t quite trust you yet. You just have to prove to each of them that you’ve changed. Some of them may never change their minds. It all depends on the person.”

“What?!” Bill shouted. “How rude! Human beings mess up all the time! I thought forgiveness was a virtue in your inferior human society!”

“Hey!” Dipper chastised. “Yes, it is. Why do you care so much what she thinks of you? You always seemed to think Mabel was silly and selfish. Have you changed your mind?”

“No.” Bill deadpanned. “If anything, I think it even more now! I want her approval because of you! You do anything your sister says. Even if you don’t want to. If she tells you not to be with me you might do it eventually! I need her permission to be with you and damn it I’m going to get it!”

Dipper snorted, and then laughed. Laughed joyously in a way that made Bill’s anger melt away nearly instantaneously. Dipper’s arms wrapped themselves around the demon and pulled him in. Bill was sprawled between the human’s legs, lying on top of him with his head pressed against the human’s heart. “Bill, that’s so… I guess romantic of you.”

“Does that mean I don’t need her permission?” Bill grunted.

“No. If Mabel approved of you, that would be really important to me.” Dipper sighed into Bill’s hair. “But I’m aware that she may never forgive you. It really hurts. To be forced to chose between two people I… really care about.” Bill noticed Dipper’s avoidance of the word _love_ with a pang of hurt. “I don’t want to choose. I don’t want Mabel to turn her back on me if I pick you. Because I’m not picking you over her! Mabel sees herself as like, the matchmaking queen. Who I’m with is probably important to her. But it’s not her choice. If I pick you, it’s because _I_ approve of you. And no one else.”

Bill flushed with pleasure and buried his face further into Dipper’s arms. Listening to the pulsing of blood rushing through his heart.

Mabel watched the two unawares from the stairs, biting her lip when she saw Dipper’s content smile.

He never looked like that around Wendy.

Bill seemed to make her brother feel comfortable, and at peace. The way Bill was cuddling up to Dipper, and pining for her approval. He really did _care_ about her brother. But how could she give her approval to someone who took him as a trophy during the apocalypse? How could she give her approval to the one who _started_ the apocalypse? Mabel shook her head.

She had to think about it for a while.

* * *

Bill sat on the porch during his break, looking at the falling leaves and trying to commit the image to memory. The summer he fell in love with his soulmate was dying, and the world would soon move on. He didn’t want to forget the special moment on Earth. And it was beautiful out. He drank from the off-brand soda the Mystery Shack had stocked in their vending machine. Peachy. Literally. With a peach pit in the bottom. He spat the seed out onto the lawn. The screen door squeaked behind him. Bill didn’t turn around. He knew who it was.

Mabel Pines walked quietly over to sit next to Bill. Quietly opening her own can of soda. Bill didn’t look at her still. But she looked at him. The young face of the human body he inhabited, his single golden eye, and the eyepatch he’d taken to wearing over the empty eye socket on his left side. The rolled-up dress sleeves, revealing the glittering golden mark that her brother had worn since birth. It was strange, Dipper’s was a much more natural color, a faded brown that led them to believe it was a birthmark. Seeing it in gold was striking in a way Dipper’s wasn’t. Bill was special. He was loud and unique and colorful like his soul mark. Dipper was more humble, like his own. But each was special. Each of them belonged to each other.

Dipper would probably end up with this guy whether she liked it or not. The universe wanted them to, for whatever reason. Her brother was the coolest, smartest, kindest person Mabel knew. So if this demon was his perfect match, how bad could he be really?

“You’ve got to _promise_ to take care of my brother.” Mabel said, the first words between them. Bill raised his brows, but didn’t say anything. “He’s really special, and you’re going to be lucky if you can have him. So you give him everything, and make him happy and safe. That’s the only way I’d ever accept it.”

Bill held out a hand, flickering with blue flames. Mabel watched them dancing for a moment, making deals with Bill was historically a bad idea. But maybe, if he was going to be with her brother, she would have to take a leap of faith. “Promise you’ll love him.” Mabel demanded.

“Shooting Star, I couldn’t resist even if I tried.” He promised.

Mabel grasped Bill’s hand firmly, squeezing tight as they shook. They flared and subsided, gone as fast as they came. Bill gave her a sincerely happy grin.

“Thanks for your blessing.” He drawled.

Mabel smiled; a smile full of dark promise. Bill was nearly proud. _That_ was someone he could call his sister in law. “Don’t make me regret it.” She warned.

* * *

Dipper was _really_ confused.

Bill and Mabel were getting along swimmingly now. Like old friends. It unsettled everyone in the house to see such a sudden change of dynamic. Stan watched out of the corner of his eye and pretended to have no interest. Ford observed and took notes like it was some natural phenomenon he was studying. Wendy outright asked “what the heck is going on between you two?”

“I gave Bill my blessing.” Mabel said. As proof of the supposed blessing, she slapped a glittery sticker on Bill’s torso. One that read “Mabel seal of approval.” Bill looked at it with surprise. He recalled her mentioning the Mabel seal of approval at one point. But didn’t realize it was a real, tangible thing.

The whole house came to a screeching halt. Dipper’s jaw dropped open in shock. Stan shouted obscenities. Ford gave Bill a dirty look, flipping open to a new page in his notepad and writing “demonic possession.”

“That’s impossible!” Stan yelled. “Mabel, sweetie, be reasonable. There’s no reason to give that evil little twerp your blessing.”

“Oh, Grunkle Stan, I completely understand.” Mabel said sympathetically, patting her Grunkle on the back. “But you see, love has a certain element of fate. Some people are meant for each other! You have to respect the mysterious ways of the universe. I would never sign off my twin to someone who wouldn’t be good for him. You’ve got to trust the special knowledge of an expert matchmaker!”

Stan silently fumed. “Pumpkin, he’s a demon.”

“Grunkle Stan, I know it’s all very confusing. But I’m going to ask you to trust me. Just like I trusted you when I didn’t turn off the portal.” Mabel said seriously. Stan shut his mouth instantly. “Bill is going to be a great addition to the family! Now, I’ve got to get dinner started. I’m making tacos! Bill, please help me in the kitchen.”

“No problem, Shooting Star. After you.” Bill gestured the human girl through the doorway. When she was in the other room, Bill gave Stan a victorious grin. Which just made Stan groan and slump against the doorway.

“Kids. I’ll never understand them!” He gripped.


End file.
